This is a tentative identification. There was an H. Ray (Private, Middlesex Regiment) who was born in Battersea and died on 26 March 1918.

Information from the censuses

Henry Ray, 13, was at school in 1911. He lived with his family at 17 Mary’s Buildings, Tanswell Street, north Lambeth, where the family of nine had four rooms. Daniel D. Ray, Henry’s father, was 40 and worked as a costermonger. He was born in Southwark. Catherine Ray, 39, was from Ireland. The couple had eight surviving children (of nine), of whom seven were at home:
Daniel P. Ray, 17, a costermonger
George Ray, 15, a news boy (sold newspapers)
Henry Ray, 13
Mary Ann Ray, 11
Margaret Ray, 8
Catherine Ray, 6
William Ray, 3
All were born in Southwark.